双瑞利衰落信道下最大比合并性能研究

基于接收信噪比的统计特性,研究了双瑞利衰落条件下各分集支路衰落幅度不平衡时最大比合并MRC接收系统的差错和分集性能。采用基于矩生成函数的方法导出了涵盖多种调制方式的平均误符号率ASER的通用公式,并得到了其Chernoff一致界。仿真结果表明:双瑞利衰落下采用MRC接收技术可以大大减小传输系统的ASER且能获得与瑞利衰落时相同的渐进分集增益,但在实际可接收到的信噪比范围内可获得的分集增益与满分集增益具有明显的差距;相对于单支路接收系统,双瑞利衰落下的MRC系统可近似得到满的相对分集增益。

On the performance of maximal-ratio-combining over double-rayleigh fading channels

Based on statistical properties of the receiving signal-to-noise ratio(SNR),the paper investigates the error and diversity performance of the maximal ratio combining(MRC) receiving system under non-identical double-Rayleigh fading conditions.A generalized formula on average symbol error rate of various M-ary modulations is derived through moment generating function based approach and its Chernoff union bound is obtained.Simulation results reveal that the ASER of a transmission system in double-Rayleigh fading decreases greatly by applying MRC receiving technique in it.The MRC receiving system achieves the same asymptotic diversity gains of double-Rayleigh fading as those of Rayleigh fading,but the diversity advantages achievable have apparent margins with full diversity gains within practical receiving SNR ranges.The full relative diversity advantages of the MRC receiving system can be obtained approximately in comparison to single-branch receiving system.